RENO, Nev. (KRNV & MyNews4.com) -- 500 thousand people a year die of heart disease and the biggest way to make sure you're not one of them is to know your risk.

"It is the number one risk of dying," said cardiologist Dr. Joseph Stevenson.

But Stevenson said that doesn't mean there's nothing you can do to prevent heart disease.

"Over the last 22 years we've made great strides in decreasing the risk through disease modification," he said.

Stevenson said there are five major risk factors: smoking, high cholesterol, diabetes, high blood pressure and a family history of heart disease.

"Family history is only if dad had heart disease in his 50's or mom in her 60's," Stevenson said. "People in their 70's and 80's do have heart disease to begin with. We see it in that decade. That alone is not considered a family history."

If your parents do have any of those risk factors Stevenson said you should start getting checked much younger than you might think.

"If mom and/or dad have high cholesterol, kids at age 20 need to get tested for dyslipidemia because it is a modifiable risk factor," he said.

Stevenson said the same goes for high blood pressure and diabetes.

If you don't have any family history and are generally healthy the tests can usually wait until your 40's or 50's.

"Then I think a good healthy lifestyle as far as limiting alcohol intake, and not smoking, and regular exercise I think would be a good prescription in that situation," Stevenson said.

He said knowing the symptoms of a heart attack could save your life if you do have one.

"If people have chest pressure, feels like sometimes someone is sitting on their chest, sometimes that pain or pressure sensation can radiate up into the jaw, into the left arm, could make them sweaty, nauseous," Stevenson said. "If someone gets those symptoms they need, in fact, to present to the emergency room as soon as possible."

But you shouldn't wait until you have a heart attack to think about heart disease, and Stevenson said managing your risk starts with talking to your primary care physician.